How do I not get confused between using 'Ser' and 'Estar'?

Both 'ser' and 'estar' both translate into English to mean 'to be'. However, this does not mean that they are interchangeable and it is essential that you learn the different uses of each verb. In order to learn the uses of 'Ser', I would learn the initialism T.I.C.T.O.W: Telling the time, Identification, Characteristics, Time and place of event, Origin, With the preposition 'de'.

Ejemplos:

Origin: Juan es de Espana/ Juan is from Spain                                                                                        

Caracteristics: Soy muy alto y delgado/ I am very tall and skinny                                                              

Time and place of event: La clase es a las ocho/ the class is at 8 O'clock

If the sentence you are trying to write does not follow one of the rules above, it is more than likely that you have to use 'Estar'.